Control mechanism for hydraulic power units



Sept. 26, 1950 J. F. MoRsE 2,523,665

CONTROL. MEcHANIsM FOR HYDRAULIC POWER UNITS Filed Nov. 18, 1947 :s sheets-sheet 1 ATTORNEYS Sept. 26, 1950 J. F. MoRsE 2,523,665

coNTRoL MEcHANIsM RoR HYDRAULIC POWER UNITS Filed Nov. 1a, 1947 5 Sheet's-Sheec JOHN F MORSE ATTORNEYS Sept. 26, 1950 J. F. MORSE 2,523,665

CONTROL MECHANISM Fox HYDRAULIC POWER UNITS s sheets-sheet 5 Filed NOV. 18, 1947 INVENTOR JOHN F MORSE BY gy ATTORNEYS Patented Sept. 26, 1950 CONTROL MECHANISM FOR HYDRAULIC POWER UNITS l John F. Morse, Hudson, Ohio Application November 18, 1947, Serial No. 786,654

15 Claims.

The present invention relates to improvements in control mechanisms for power units of the type in which the parts are operated by hydraulic pressure controlled by a valve or the like which admits and discharges fluid pressure from the sides of a double-acting piston. The valve is actuated by a manually operated device such as a wheel or lever' and the mechanism is usually so arranged that the direction of movement of the manual device is the same as the direction in which the part or machine element is to be moved.

Various power units of the type outlined have been perfected and are generally known as servotype hydraulic boosters. The pressure iiuid usually employed is a light oil which is supplied under pressure to the valve by which the oil under pressure is transmitted vto either side of the piston. The piston is connected directly to the parts of the machine which are to be moved.

In previous power unit assemblies theV piston stops at the full limit of'its stroke in either direction and the mechanism which is operated thereby is thus held at its extreme position until the piston is reversed by the reversal of the manf ual control. It has been found, however, in certain types of machinery or installations that, while the mechanism should be initially moved to the full extent, it is not desirable to hold the mechanism at the extreme limit of its movement vbut to slack or ease 01T the pressure Vexerted by the piston to a greater or less extent after the mechanism has reached either limit of its movement. If easing oitv of the pressure is left to the operator it will more often not be done at all and injurious results may occur due to the retention rection. Thus, as the manual control device'approaches the extreme of its movement, the valve is automatically reversed and the piston recedes slightly from its vextreme position. This operation is accomplished without reversing the direction of the manual control, and automatically introduces into systems of this type provision for y relaxation of the extreme pressures at the end of the operative stroke of the manual control dev1ce.

While the improvement in power units as outlined above is useful in connection with many types of machinery and the invention may, therefore, have a wide range of usefulness, it is particularly intended yand designed forpower shifting marine transmissions. Marine transmissions should have some .provision for relieving the thrust at the end of each stroke so that excessive wear on theA thrust ybearing will be avoided.

Brief-1y stated, the mechanism which operates the valve inthe invention as illustrated and described is-so designed and arranged that during the nal stage of movement of the manual control device the valve is reversed slightly after completing its full stroke in either direction. This reversal cracks the -valve so that thepressure fluid acts in reverse for an interval just su'icient to cause the piston to recede to an extent necessary torelieve the extreme outward pressure on the piston. 'TheV operation is automatic, the operator shifts the manual control to its extreme, and without further attention on thev part of the operator the transmission, or whatever machine part is operated, is moved to its extreme position and then backedof to an extent set by the mechanism. The organization is such that it does not interfere with thenormal operation of the poweriunit.,

In the drawings there is illustrated a preferred embodiment of the invention by which the advantageous results may be'secured. However, the invention is not'conined to the mechanism shown'and described but may be embodied in other forms and may be improved upon and modified without departing from the essential features which constitute the invention. One form of servo-type hydraulic booster cylinders is shown, together with a specic form of valve, but the invention may be applied to other forms of boosters and valve mechanisms.

In the drawings in which the best known and preferred form of the invention is shown,

Fig. `1 is a View showing the position of the mechanism when the cylinderassembly is in hydraulic balance at neutral. In this position the pressure fluid flows through the system at minimum pressure. In this ligure, as well as in the companion views, Ycertain parts have Vbeen re-r moved and others are in section.

Fig. 2 shows .van intermediate position of the parts when the piston is moving toward the right. Y

Fig. 3 showsthe condition when the piston has moved to its extreme right-hand position, which iswhen the parts moved thereby are home Fig. 4 shows the position of the parts at the end of movement" of the manual control, showing how the valvejis cracked and the piston has receded to relieve the thrust on the parts operated thereby.

Fig. 5 is a view similar to Fig. 3 but showing the piston at the eXtreme left-hand position.

Fig. 6 is an enlarged section on the line 6-6 of Fig. l.

Fig. '7 is an enlarged section on the line 'I-'I of Fig. l.

The power unit and control mechanism shown herein is carried by two parallel supporting plates I which are substantially triangular. At the lower left-hand corner of the plates are located holes 2 by which the unit may be attached to some stationary part, such as the base of a marine engine. The right-hand portions of the plates are received over the shaft 5 which is the shaft to be actuated by the power unit and in case the power unit is intended to operate a marine transmission this is the shaft which operates the transmission. Extending across the plates I near the upper left-hand corner is the shaft 6 on which the power unit, indicated in general by the numeral 6, is rotatable.

The power cylinder as shown herein is comprised of a central chamber II) in which the piston II reciprocates. The left-hand end of the cylinder is closed by a head I2 which is pivotally mounted on the shaft 6 between the plates I. The Vright-hand end of the cylinder is closed by the head I4 having a central passage I5 through which the piston rod I6 reciprocates. A heavy spring-held packing I8 in the interior of the head I i prevents the seepage of the oil around the piston rod I6 and a wiper I9 keeps dirt from entering the system. Head bolts 26 hold the cylinder assembly together.

l Threaded on the outer end of the piston rod and fixed by a pin 24 is a heavy yoke 25, the rear or right hand end of which is bifurcated as at 26 to form a clevis in which is received the upper end of a lever arm 28, the parts 26 and 28 being connected by the removable pivot pin 36. This pin has a head 3| on one end, the other end being apertured to receive the locking dowel 32 carrying the swinging nger grip 34. Removal of the pin 36 permits the piston to be disconnected from the transmission shaft in case of failure of the power unit. A swinging hand grip 36 is connected to the yoke by which the power unit may be raised. On the upper side of the yoke 25 are formed two parallel vertical guideways 38 to receive a portion of the valve-actuating mechanism, as will be described.

In order to adjust the stroke of the piston so as to bring it in the proper relationship to the desired rotation of the shaft 5, the lever 28 is provided with ne threads along its major portion and this part of the lever is received in a splitthreaded yoke 46 arranged to be clamped about the lever 28 by bolts 42. The yoke 40 is formed with the transverse split bearing 43 which is received over the shaft 5 and squeezed in clamping relation thereon by the bolts 44.

In the lower side of the cylinder I are the two inlet ports I) and 5I, which lead to the opposite ends of the piston cylinder by which the pressure uid is admitted to or discharged from the cylinder, as the case may be. These passages are brought into proximity in the wall of the cylinder where they register with passages in the side of the valve block 53 attached to the side of the cylinder.

Interorly of the valve block is the longitudinal valve passage 55 with which the passages 50 Cil and 5I connect, and from the opposite side of the passage 55, a centrally located passage 56v leads to the exterior of the valve block where it is connected to the intake conduit (not shown) from the pressure supply. The outlet passage from the valve chamber is indicated at 5l and is connected by two branches 5'Ia and Sib to points near the opposite ends of the valve passage 55.

The valve proper, which is indicated at 60, is sleeve mounted on the end of a valve rod 6I, reciprocating in the valve block 53, seepage around the valve rod being prevented by bellows-like seals at either end indicated by the numerals 63 and 64. The left-hand bellows 63 is enclosed by a cap 65. The right-hand end of the valve rod is connected by pin 66 to a valve-operating link 68.

The valve proper is provided with the central recessed portion 'I6 which establishes communication between the inlet passage 56 and the passages 56 and 5I. Recessed portions 'IIE and IIb in the valve proper establish communication respectively between the passage 5I and outlet passage 5la or between the passage 50 and the outlet passage 51h.

In the position of the parts shown in Fig. 1, when the device is in neutral position, the valve is at its midway position and all of the ports are in communication so that no motion is transmitted to the piston. In the position shown in Fig. 2 the passages 5I and 55 and the passages 56 and 53h are in communication so that the piston is moving to the right. In the position shown in Fig. 5 the passages 56 and 56 and the passages 5I and 57a aie in communication so the piston is moving tothe left.

In the position shown in Fig. 4, the valve 66 has been shifted slightly to the left cracking the valve socommunication is reestablished between the passages 56 and 5I) and between the passages 5I and Ele. As shown, this is but a slight opening as the valve has moved only a short way to the left, but it is suiiicient to give the requisite return movement to the piston II so as to relieve the extreme thrust on the shaft 5.

The mechanism which operates the valve 56 through the rod 6I and link 66 is supported in a pair 0f vertical side plates 'I5 which are attached to the valve cylinder and lie between the plates I. The link 68 is xed at its far end to a transverse pin 'I6 by set screws TI, the ends of the pin being movable in slots 'I9formed in the plates 15. (See Fig. 7.) On either side of the link 68 the pin 'I6 is rotatable in sleeves 86 which extend inwardly in opposite directions from tWo parallel, vertical, swinging arms 18.

These arms 'I8 are bent as shown in the drawings and at their upper ends are connected by a transverse bolt 82 which pivots and moves vertically in the guides 38 heretofore described as a part of the yoke 25. Across the lower extremities of the arms 'I8 is a second transverse pin 84 and pivotally mounted on this pin between sleeves 85 is the head 86 of a link 88, which is adjustable by the screw-threaded connection 89 between the head and the main portion of the link.

Connected to the link 88 through the ball bearing 96 (Fig. 6) is a transverse stud 92 which is fastened in the lower end of a swinging arm which is fixed at its upper end on the hubof a lpinion 96. The pinion 96 is rotatably mounted on a stud 97 which is fastened in an extension on the lower side of one of the plates '15. Y

The pinion 96 is in mesh with a sector gear IDO 12h31? iS fixed by pin 99 to a transverse operatshown), but which would be located in thev pilot house or at any other control station. 1

It will be seen that as the shaft lili is rotated the gear lili), pinion S6 and link 88 and arm 18 will shift the valve 6o in either direction to move the piston H t the right or left. It will also be noted that the links 88 and 95 constitute a toggle and when the link 86 and arm 95 are at dead center with the points B4, 91 and 92 in direct line, whether in the position shown in Fig. 3 or 5, the piston is at the extreme of its movement either to the right or to the left. However, if the rotation of the shaft lill is continued beyond this dead-center position in either direction the `is employed, in the same direction as it is desired to shift the part operated by the power unit.

What is claimed is: 1. In a power unit of the type set forth, having a piston and cylinder, a driven element, connections from the piston to a driven element, a

valve to admit and discharge pressure fluid to and from opposite ends of the cylinder, a rotatable control shaft, connections from the control shaft to shift the valve, said connections including a crank and a link which are in dead-center position when the piston is at an extreme of its movement, and means to arrest the movement `of the shaft after the crank and link have passed the dead-center position.

2; In a power unit of the type set forth, havinga piston and a cylinder, a driven shaft, conarm 95 will continue its movement and the arms `'I8 will be moved in the opposite direction and the valve will be opened; Such a condition is shown in Fig. 4 where the arm 95 has moved slightly beyond the position shown in Fig. 3. The same condition will eXist, only on the opposite side, if the arm 95 is moved counter clockwise beyond its position as shown in Fig. 5.

It is desirable to move the arm 95 beyond its dead-center position to a limited extent as it is `the intent to move the shaft 5 only to a degree which will reduce the pressure sufficiently to relieve the wear on the thrust bearing. For this purpose adjustable stops are provided to arrest the movement of the shaft lili and the parts operated thereby in either direction when the parts are in a position such as illustrated in Fig. 4. The mechanism for this purpose shown in the illustrated embodiment of the invention comprises a cam I In which is xed on the shaftv IUI by the pin lll. This cam rotates between the two stops which are set screws H2 threaded in a block H3 attached to the lower side of one of the plates 15. The stop screws are adjusted to the correct height `to arrest the motion of the shaft I0! and the opening of the valve 60 at the desired point. When the valve reverses by the movement of the toggle beyond dead center, the vpiston will be reversed and this movement, acting through the guideways 38. causes the arms 18 to swing about the center 84 which shifts the valve tov neutral. This arrests any further movement of the piston. Y

Reviewing briefly the operation of the device and assuming that the parts are in the neutral position shown in Fig. 1, and that theV piston is to be moved to the right, the operator rotates the shaft EDI in counter-clockwise direction, which shifts the valve 60 to the left and causes the pressure fluid to enter through the passage 5|, the oil behind the piston passing out through the passage 5U. treme limit of its movement the parts are in the position shown in Fig. 3, but the cam l I0 has not reached the top of the stop screw l l2 to the left. The operator may therefore continue the movement of the shaft which will crack the valve and cause the recession of the piston to the position shown in Fig. 4. The operation in the 0pposite direction follows the same sequence of v movement. As noted above, the connection from the operatorsposition to the link H15 should desirably be such that the operator moves the control stick or wheel, or whatever instrumentality When the piston reaches the eX-.

nections from the piston to the shaft, a valve to control the admission of fluid pressure to the cylinder to move the piston in opposite directions, a manually operated reversible element,

connections between the manually operated element and the valve operative during movement of the manually operated element in one direction to shift the valve to admit fluid pressure to the cylinder to move the piston to one extreme of itsv movement and then to shift the valve to reverse the movement of the piston to an extent substantially less than its full stroke.

3. In a power unit of the type set forth, having a piston vand a cylinder, a driven shaft, connections from the piston to the shaft, a valve to control the admission of fluid pressure to the f cylinder to move the piston in opposite directions, amanually operated element, connections between the manually operated element and the valve operative during movement of the manvually operated element in one direction to shift `the valve to admit fluid pressure to the cylinder -ment, a valve to control the admission of fluid pressure to the cylinder to move the piston in vopposite directions, a rotatable control shaft, a

toggle operated by the control shaft, an arm vconnecting the piston, valve and toggle, the pivot points of the toggle being on dead center when lthe piston is at either eXtreme of its movement,

and means to permit the shaft to move said "toggle beyond dead center at either end of its movement to a predetermined extent to reverse the direction of the valve.

5. In a device of the character set forth, a power unit comprising a cylinder and a piston therein, a valve to admit pressurev fluid vto opposite ends of the cylinder, means to shift the valve, said means comprising a manuallyl operated reversible shaft, connections between the shaft and the valve shifting means, said connections being so constructed and designed that during the latter part of one cycle of the shaft in either direction the valve is opened to an extent to cause a reduced movement of the piston in a reverse direction.

6. In a power unit of the type described, a cylinder, a piston therein, a valve to control the admission of pressure to opposite sides of the piston, an operating shaft movable in opposite directions, connections between the shaft and the valve, said connections causing the valve to move to a position to reverse the movement of the piston to a restricted extent during the last portion of the movement of the shaft in either direction.

7. In a power unit, a cylinder, a piston therein, a valve to control the admission of pressure to opposite sides of the piston, a rotatable operating shaft, stops to limit the movement of the shaft in either direction, connections between the shaft and the valve and means in said connections to reverse the valve before the movement of the shaft is arrested by vone of said stops.

8. In a power unit, a cylinder, a piston therein, a valve to control the admission of pressure to opposite sides of the piston, a rotatable operating shaft, stops to limit the movement of the shaft in either direction, connections between the shaft and the valve and means in said connections to reverse the valve immediately before the movement of the shaft is arrested by one of said stops.

9. In a power unit, a cylinder, a piston therein, a shiftable valve to control the admission of pressure to opposite sides of the piston, a rotatable operating shaft, a stop to limit the movement of the shaft in one direction, operating connections between the shaft and the valve, said connections including a togglelink, the stop being so located as to arrest the movement of the shaft after the toggle link has passed dead center.

10. In a power unit, a cylinder, a piston therein, a shftable valve to control the admission of pressure to opposite sides of the piston, a rotatable operating shaft, a stop to limit the movement of the shaft in one direction, operating conn nections between the shaft and the valve, said connections including a toggle link, the stop being so located as to arrest the movement of the shaft after the toggle link has passed dead center and after the valve has 4been shifted in reverse and said piston has thereby retreatedito a point short of its extreme position.

11. In a power unit of the type described, a reversible manually operated control shaft, a cylinder, a piston in the cylinder, a valve to admit fluid pressure to opposite sides of the piston, a driven shaft connected to the piston, connections between the control shaft and the valve operative during movement of the control shaft in either direction to shift the valve during a single cycle of the control shaft, rst to move the piston outwardly to its extreme position in one direction and then to reverse the valve and cause the piston to recede to a limited extent from its extreme position.

l2. In a power unit of the type described, a manually operated control shaft, a cylinder, a piston in the cylinder, a valve to admit fluid pressure to opposite sides of the piston, a driven shaft connected to the piston, connections between the control shaft andthe valve to shift the valve during a single cycle of the control shaft, first to move the piston outwardly to its extreme position in one direction and then to reverse the valve and. cause the piston to recede from its extreme position and means to arrest the movement of the piston at a point just short of its extreme outward position.

13. In a power unit, a manually operated control shaft, a cylinder, a piston in the cylinder, a valve to admit fluid pressure to opposite sides of the piston, a driven shaft, a crank arm connected to the shaft and to the piston, a swinging arm one end of which is movable with the piston, a link connecting the swinging arm and the valve, a toggle link, one arm of the toggle being pivoted to the swinging arm, the other arm of the toggle being rotatable by the control shaft and stops to arrest the movement of the shaft after the toggle has passed dead center in either direction of its movement.

14. In a power unit comprising a cylinder, a piston therein, and a valve to admit fluid pressure to opposite sides of the piston, a reversible manually operated control lever, connections from the control lever to the valve for operating the valve, and means in said connections to cause the piston to recedeto a limited extent from its extreme position during a single stroke of the control lever in either direction.

l5. In a power unit comprising a cylinder, a piston therein, and a valve to admit fluid pressure to opposite sides of the piston, a reversible manually operated control lever, connections from the control lever to the valve for operating the valve, and means in said connections to cause the valve to reverse the direction of its movement and thereby reverse the movement of the piston to a limited extent during a single stroke of the control lever in either direction.

- JOHN F. MORSE.

REFERENCES CITED The following references are of record in thele of this patent:

UNITED STATES PATENTS Number Name Date 1,058,271 Sundh` Apr. 8, 1913 1,339,939 Alter May 1l, 1920 2,055,530 Hallenbeck Sept. 29, 1936 2,131,481 OConnor Sept. 27, 1938 2,284,298 Newton May 26, 1942 

